Rheostat



YFeb. 15, 1927.

F. W. KAISLING RHEOSTAT Filed April 3, 1924 Patented Feb.A 15, 1927.

. ...afvalt UNITI-:D STATES PATENT OFFICE.

FRANK WILLIAM KAIVSLING, OF CHICAGO, ILLINOIS, ASSIGNCR TO KELLOGG SJVITCH- "BOARD AND SUPPLY COMPANY, F CHICAGO, ILLENOIS, A CGRPORATION OF ILLI- Y NoIs.

. Application led April 3,

My invention relates to rheostats used in Y connection with an electric circuit for varying the reslstancetherein and more particularly for use in controlling the current How th'ro'ughfthe lilament of an audion or elec- 'n tron tube; and an object of my invention is to providea rheostat which is simple in construction and operation but veryl durable and efficient.

A feature of my invention is the provision of an Vimproved helically wound resistance unit supported between a pair of disk members which when clamped together securev i provision of a pair` of spring contact wipers which havetheir free ends so formed and shaped thatthey correspond Vto the contour ofl my resistance element and are adapt-ed to engage and insure lpositive contactual engagement therewith. VStillanotherf feature of my invention is the provision of an insulation member ior Vseparating the ends o'l the. resistance elementrof my invention and the manner in which the said insulation member is secured in place to separate the ends of said resistance element. f Y

The above features, as well as others.l will Ybe morel particularly pointed out in the ensuing Specilication and for amore complete understanding' of the rheostat of my invention reference may be had to the accompany ing drawing in which like reference characters,in t-hexseveral. views denote like parts, and inwhich; Y` .Fig..1 is a side view ot' the rheostat of my invention;l Y

- Fig. Qisa front plan View of the rheostat RHEOSTAT.

1924. Serial No. 703,926.

of my invention showing a part thereof removed to expose one of the spring contact wlpers; Y

Fig. 3 is a sectional view along the line 3 3 of Fig. 2;

Fig. 4. is a back yplan view of my invention with certain parts removed;

Fig. 5 is a sectional view or the rotatable resistance carrying unit of my invention taken along the line ot' its equator; and

Fig. 6 is a plan view of one of the disk members of the rotatable unit of my inventlon. f

Referring now more in detail to my invention las illustrated in the accompanying drawing, the rheostat of my invention comprises a helically wound resistance unit 2 ofa plurality of convolutions 3, constructed of suitable resistance material and ofa predetermined resistanee. rlhe rotatable unit R which supports the resistance unit 2 comprises a pair of disks l and 5 moulded of suitable insulation material such as bakelite. As the disks 4 and 5 are identical in construction a description of one will suftice. In one face oi' each of the disks and integrally formed therewith is a raised portion 6 near the peripheryv and in the shape of a ring. The outer vperipheral edge 6 of the ring 6 is arcuate shaped and adapted to form a channel for receiving and engaging the convolutions 3 or the resistance element 2 as will be pointed out more in detail later. A hub member 7 is provided in the center of each of the disks 4 and 5 and integrally formed therewith, said hub member 7 beingy of a size slightly thicker than the thickness of the ring portion 6 for purposes hereinafter described. An orilice 8 is provided in each disk 4 and 5 as is also a plurality of orifices 9.

Having described the construction of the disks 4 and 5 I will now describe how the rotatable unit R is assembled and the resist-V The two bers 7 engage each other and the faces of thev ring portions 6 are opposite each other, the faces of the ring portions 6 do not engage each other but are slightly separated by an air gap 10 due to the thickness oi the hub members 7 which prevent the engagement of the ring portions 6. At the same time the disks 4 and 5 are being placed together' the resistance element will engage the circumferential channel 11 formed between the disks 4land 5 by the ring portions ti and the peripheral edges of said disks. rthe channel 11 formed by the disks 4 and 5 and by the ring shaped portions 6 ot said disks is ot such al size that the peripheral edges ol the disks 4 and 5 extend slightly above the center or diameter ot the convolutions 3 oi: the resistance element 2 whereby a uniform top portion of each convolution 3 is exposed and adapted to be engaged by contact wipers 21 and 22. To secure the disks 4 and 5 together a sleeve member 12 is provided which has a colla-r 13 'integrally formed therewith and is adapted to extend through an opening in a conducting member 14 and then to pass through the openings 8 in the disks 4 and 5 and then through a .vasher 15 where it has a shoulder portion 16 upset to prevent its removal wereoy the disks 4 and 5 are secured together, the washer 15 engaging one ot the disks, while the collar 13 and conduct-ing member 14 engage the other of said disks. To Ysecurely clamp the resistance elementv 2 between the disks 4 and 5, screws 17 are provided which extend through the openings 9 provided in the disks 4 and 5 and then have screw-threaded engagement with nuts 18. riilie nuts are screwed down on the screws 17 to cause the ring portions 6 otl the disks4 and 5 to come together and close the air gap 10 whereby the resistance element 2 is securely clamped in the channel 11 against displacement. rlhe screws 17 and nuts 13 bring the ring portions 6 together which will reduce the size ot the channel 11 and clamp the resistance element 2 between said disk members 4 and 5 to t'orm the rotatable unit R. One end 2 of the resistance element extends through a suitable opening in disk 4'and is then turned over to prevent its removal, while the other end 22 of said resistance element 2 extends through a suitable opening in the disk 5 and an orifice 14 in the conducting member 14 and is then bent over to connect the end of the resistance element 2with the sleeve 12 which is in turn conductively connected to the terminal 30. To separate the ends ot the resistanceelement 2 a piece of insulation 2O corresponding in shape to the cont-our of the channel 11 is provided which engages and separates the respective ends ot said resistancelelement 2 and is clamped in the-channel 11 between the disks 4 and 5 in the same manner as described in connection with the resistance element 2. The insulation member 2O has a uniform portion oi? its body exposed out of the channel 1 and above the periphery ot the disks 4 and 5 which exposed portion corresponds in size and contour to the exposed portion of the convolution 3 and is adapted to be engaged by the ends 21 and 22 when my rheostat is in its oli' normal position in which position the resistance element will not be included in the operating circuit. The screws 17 by engaging the aligned orifices 9 secure and clamp the disks 4 and 5 together to prevent turning ot one disk relative to the other on the sleeve 12, and also clamp the resistance `element 2 and insulation member 2O in the channel 11 i'ormed by the disks 4 `and 5 which has been placed therein during the assen'ibly ot the disks 4 and 5 as has already been described.

rthe spring contact wipers 21 and 22 are provided tor engaging the helical resistance element and are separated by means of a suitable terminal block 23. A pair oii mounting legs 24 and are provided between which the terminal block 23 and wipers 21 and 22 are clamped by means ot suitable cramping screws 2G. The terminal block 23 and wipers 21 and 22 are suitably insulated trom the mounting legs 24 and 25 by means ot suitable insulation strips 27 and the clamping screws 26 which pass through suitable orifices in the mounting legs 24 and 25, terminal block 23, wipers 21 and 22, and insulation strips 27 have screw threaded eneinent with suitably tapped orifices in a terminal block 28 and are insulated from the terminal block 23 and wipers 21 and 22 by insulation bushings 29. Suitable terminals 30 and 3l are secured to the terminal blocks 23 and 28 by means ot srrews 32. Theiree ends 21 and 22 o't the wipers 21 and 22 are bent over and so :t'ormed that they correspond to vthe contour o't the exposed por-4 tion ot the resistance clement 2 which extends slightly1 above the circumferential edges oiE the disks 4 and 5 due to the position et the ring t5 which renders the channel 11 shallow enough to cause a uniform portion ot each convolution ot the resistance element 2 to extend above the disks 4. and 5 as has just been described. The free ends 21 and 22 ot wipers 21 and 22 are adapted to make contact with several ot the convolutions 3 ot the resistance element 2 at the saine timeand are ot such spring tension that fl contactual engagenicnt is insured at -1 f n.. The portions 212 and 222 ot the and 22 respectively are flared outward to permit itree rotation of l resistance element 2 between they bent over ends 21 and 22 of the wipers 21. and 22.

rlie unit und its `upportcd pausas a whole areiotatably supported betwceni, the

of the end l2 ot the stop pin 4:1 to limit the.

- legs y241i and 25 and to position and rotatably support the same, the unit R is inserted between legs 2d'and 25 with the insulating member resting between the ends 21 and 22 of wipers 21 and`22. i sli-att -l is now inserted through an oriitice in the leg 2st collar 13 of the sleeve'12 is provided and Cin -collar 13 and' the inner face ot the leg y produces' affrici'iional eii'ect between the end adapted to have its end engage the shait to secure the unit R as a whole to the shaft 34 so that when the actuating knob 51 which is secured to the end lof the shaft 34 in any suitable manner is turned the shaft 3d which rotates in the bea-rings and 3G in the legs24f and 25 and its support unit R rotate as a whole to place the convolutionsr of the resistance element 2 in engagement with the wiper ends 21V and 22 to include certain amount ot resistance in the operating cire-uit in which `my rheostat is being used and when the rotatable unit It is rotated back to its'normal position the insulation separator .20 wiil again engage the wiper ends 21 and 22.

lVhen the rotatable unit R isrotatcd and the resistance element 2 passes between and engages .the ends 21 and 22 ot' Contact wipers 21-and 22, the convolutions 3 are mainl tained uniformly spaced and in their correct position by the clamping eifect ot' the Vdiskstand by the screws 17 and nuts 1S, so that there no creeping ot the resistance element 2 in the channel 11.

The set screw 37 prevents removal oi' the shaft 'l-'t and fto maintain the rotatable unit It in any of its adjusted positions I provide. a dished or spring washer 39 which when insertedbetween the end ot the sleeve 12 or of the ysleeve 11 or collar 13 and the les tohold the rotatable unit R in'any orn itsV adjusted positions. I provide a stop pin Y' 40 which entends'through a washer 41 and then through suitable aligned openings in and and member 14 and then has its end staked over to prevent its being removed trom the rotatable unit R, the collar, L11 engaging therwasher 41.` The stop pin 4() vtakes the place ot a screw 1T and nut 1S a-nd'assists to clamp the disks 4 and 5 together to' cause rino' portion 5 to enoao'e Y e la l. 'cfs rrr each other, andV also to maintain the conducting member la in place. VThe stop pin 40 .is adaptedto engagea suitable stop pin tlsecured to the leg 2e in the path et' travel rotation of the unit R in its oit and extreme on7 positions.

' To Vmount my rheostat the actuating knob 51 may be removed and the end of the shaft 34 inserted through a suitable opening in a suitable mounting member 52 and to secure the rheostat to the member 52 a screw 53 is lVhat I claim as new and desire to secure by United States Letters Patent, is as follows:

1. A device of the class described including a resistance element, a pair of disk members, each provided with an integrally formed hub member and an integrally iormed ring body portion near its periphery, the hub member being of a greater' thickness than the thickness of said ring body portion, means for clamping said pair ot disk members together in matched relation so that said ring body portions form a channel ior receiving said resistance element, said ring body portions being slightly separated due to the thickness ot' said hub members, and means for engaging said disk members for bringing said ring` body portions together to clamp said resistance element in position between said disk members.

2. A device of the class described includinga helically formed resistance element, a pair of disk members, a ring integrally formed with each of said disk members near the periphery ot the disk member, another ring for each of said disk members. and of a greater thickness than the thickness of said lirst ring, means for securing said disk members together in matched relation, said iirst rings forming a channel between said pair ot disk members tor receiving said resistance element. said first rings forming said channel being separated du'e to the thickness ot' said other rings and being positioned to cause said resista-nce element to extend slightlyl above the periphery of said disk members, and means for clamping said .irst rings together to clamp said resistance element in said channel against displacement.

A device of the class described including a resistance element, a pair of disk members adapted to be clamped together, a pair of ring body port-ions integrally 'formed with the inner faces and nea-r the periphery et said clamped disk members to 'form a channel :tor receiving said resistance element, other ring. body portions for said pair ot disk members for separating said rst ring body portions, and means for clamping said :lirst ring body portions together to securely clamp said resistance element in said channel against displacement, said channel being ot al depth to allow said resistance element to be exposed above the periphery ot' said disk n'icinbers.

Ll. A device ot' the class described including a resistance element, a pair ot' disk meniliers secured together, ring body portions integrally tormed with said dis r members to 'form a channel Jfor receiving said resistance element, hub members integrally t'ormed vith said disk members and adapted to provide an air gap between said ring` body portions to render said channel oi sutlicient size to pern'iit the adjustment ot said resistance element in said channel, and means tor engaging said disk members tor closing said air gap to securely clamp said resistance element in said channel.

5. A device oit the class described including a helically formed resistance element, a pair of disk members secured togetherv means integrally Jformed with and between said disk members to provide channel 't'or receiving said resistance element, means integrally formed With and between said disk members to render said channel ot a size slightly larger than the diameter ot said resistance element, and means 'for engaging said disk members 'for reducing said channel to a size smaller than the diameter ot' said resistance element to clamp said resistance element in said channel against displacement,

said resistance element `and said pair oit disk members forming a single operating unit.

(i. A device ofthe class described inclut ing a resistance element comprising a plurality of convolutions, a pair oi disk members secured together and having integrally formed hub members adapted to separate integrally formed ring body port'ons located near the peripheral edge of said disk and arranged to torni a circumferential channel between said disk members of a size to receive said resistance element, and means 4tor engaging said disk members for reducing the size of said channel to a size smaller than the diameter of the convolutions ot said resistance element to securely clamp said resistance element in said channel against c isplaceinent, said channel being ot such depth to'eause a uniform portion or' said convolutions to extend above the peripheral edge ot said disk members.

Tr A device of the class described including a mounting trame, a resistance element comprising a plurality of conif'olutions, a pair of disk members secured together and arranged to 'lorm a circumferential channel lor receiving said resistance element, means tor clamping said resistance element in said channel to i'orm a single unit, a portion o'i each ol said convolutions being exposed above the periphery ot said disk members, means for rotatably supporting said unit on said trame, and a pair ot springl contact Wipers secured to said frame and having their tree ends turned slightly over and arcuate shaped to contorni to the contour ot' the convolutions oit the resistance element and adapted to engage and permit the said vrposed portions ot said convolutions to pass bet-Ween said turned over arcuate shaped en ds ot said Wipers.

8. A device ot' the class described including a mounting Jtrame, a resistance element comprising a plurality ot' convolutions, s pair ot disk members secured together and constructed to torni a circumferential chan-- nel tor receiving said resistance element, said channel being ot such size` that a portion ot each olf said convolutions extends out ot' said channel and above the periphery of :s aid disk members, means 'tor clamping sai resistance element in said channel to torm a it, means 'lior rotatably supporting said r it on said mounting' trame, a spring contact Wiper secured at its one end to said mounting 'frame and having its other end bent over and shaped to contorni to the contonr ot the exposed portion ot said convolutions, the corners o't' said bent over end being l'lared up so that when said unit is 'rotated said other end will ride over the convolutions ot said resistance` element and insure contactual engagement therewith.

9. A device ot the character' described including a. resistance element, a pair ot disk members proif'ided with integrally vlformed ring` shaped ridges, hub members 'tor said dialmembers, means lor securing said disk members together so that said hub nicmbers engage each other end to end, said ring shaped ridges being positioned oiiposite each other but not in contactual engagement and adapted to torni a circumterential channel 'for receiving said resistance element, and ii-"ans tor ei'lecting contactual engagement ot laid rino' shaped ridges to reduce the size ot said channel to clamp said resistance elcinent in said channel against displacement.

l0. device oi? the class described including a resistance clement.l a mounting traine, a pair ot disk men'ibers provided with integrally termed ring shaped ridges adapted to form a groove ,tor receiving said resistance element when s il disk members are secured together, said ring shaped ridges disengaging each other to permit the adjust.- n'ient ot' said resistance element in said grooves, means including a pin :tor engagsaid disk members to cause said ridges le engage eachother vfhereby said resistance clement is clamped in said groovel between said disk members to torni a rotatable unit, a shatt 'for rotatably supl'iorting said unit on said mounting trame, and a stop pin secnredfto, said mounting frame and adapted to be engaged by said first pin to limit the extent of rotation of said rotatable unit.

t 11. yA device of the class described including a mounting frame,y a pair of disk menibersisecured together and having their inner faces provided with a pair of integrally formed liub members adapted to engage each other to separate a pair of integrally formed ring body portions to form a circumferentialA channel, means for securing said 'disk members together, but allowing y the said channel to be of a'size sufficient to permit the insertion of a resistance element adapted to lit into said channel, a pin extending through said disk members and adapted to engage said disk members to reduce the said channel to clamp said resistance' element in said channel against displacement to form a rotatable unit, a rotatable shaft for rotatably supporting'said rotatable unit on said mounting frame, and a stop pin secured to said frame and adapted to be engaged by said first pin to limit the u amount of rotationcof said rotatable unit.

12. A device of the class described including a resistancev element comprising a 'plurality of convolutions, a pair of disk together to clamp said resistance element Y, and said insulation member in said channel against displacement.

13, A'device of the class described including a resistance element comprising a plurality' of convolutions, a pair of disk members provided With ridge body portions near their peripheral edge and with integrallyy form-ed lhub members on their inner faces, said disks adapted to be secured together, the hubkv members engaging each other to separate they ring body portions to form acircumferential channel for receiving said resistance element, an insulation member corresponding to the contour of said channel adapted to fit into said channel and to engage and separate tli-e ends of said i resistance element, means for reducing said channel to clamp said resistance element and said insulation member in said channel against displacement, said channel being of a size 'to permit a uniform portion of said convolutions and said insulation member to be exposed above the periphery of said disk members, and a pair of spring contact Wipers adapted to engage the exposed portion of said insulation member ivhoii said device lis in its ofi' normal position and to iigage the exposed portion of certain of said convolutions when said device is in its on position.

1li. A device of the class described, includinga resistance element, a pair of members secured together and provided-With means, including a pair of integrally formed lhub members adapted to engage each other to separate a pair of integrally formed ring body portions located near the peripheral edge of said members to provide a circuniferential channel between said members for receiving said resistance element, an insulation member shaped to fit into said channel and adapted to engage and separate the ends of said resistance elem-ent, and means for reducing said channel to clamp said resistance element and said insulation members in said channel against movement to form a single unit with said disk inembers.

15. A device of the class described including a pair of disks having integrally formed liub members on their inner faces adapted' to separate a. pair of integrally formed ring body portions to form a channel in the peripheral edge of said disks for receiving a resistance element and partially encompassing the same, means permitting the reduction in size ofsaid channel when the said disks are clamped together to clamp said resistance element in said channel against movement, and a cylindrical meinber of insulating material separating the ends of said wire and adapted tofit into said channel.

16. A device of the class described including a pair of disks having integrally formed hub members on their inner faces adapted to separate a pair of integrally formed ring body portions to foi'm a channel in the peripheral edge of said disks for receiving a resistance element, said channel partially encompassing said resistance element to permit a uniform portion of said convolutions to be exposed above the periphery of said disks, means integral With said disks for reducing said channel when the said disks are clamped together to secure said resistance element in said formed channel against movement, and a cylindrical member of insulating material separat ing the ends of said Wire and adapted to fit into said channel.

17. A device of the class described including a mounting frame, a pair of disks having integrally formed hub members and integrally formed ring body portions adapted to form a groove in the peripheral edge of each of said disks, said grooves forming a channel when said disks are in matched relation, said hub ineinbers engaging each other to separate the edges of the disks` to permit the insertion of a resistance element in said Channel, said resistance element partially encompassed by said disks to perniit a uniform portion of the oonvolutions of said element to protrude above the peripheral edge ot said disks, other grooves in said 10 disks forming other channels, means for Clainpingsaid element in said formed chan nel to forni av unit, means Jfor rotatably supporting` said unit on said traine, and :1 wiper secured to said trame for engaging the exposed portion oii said convolutions.

Signed by me at Chicago, in the county of Cook and State ot Illinois, this ist, day of April, 1924.

FRANK VILLIAM KAISLING. 

